The present invention relates to a method and apparatus for preheating material with the hot gas being exhausted from a heater or kiln.
Preheaters are commonly used for preheating particulate material, including preheating limestone. Limestone is generally preheated by directing hot exhaust gases from a rotary calcining kiln through the limestone particulate material in counter-current flow prior to the limestone entering the calcining kiln. The gases heat the limestone particles prior to their introduction to the rotary kiln, thus requiring less heating in the rotary kiln to complete the calcining process, thus making the calcining process more energy efficient. Preheating apparatuses of this general type are known in the art.